🌊 Aquarium Filter Flow Rate Calculator
Find the right filter GPH for your freshwater tank based on stocking and tank size.
Results
Minimum Filter Flow
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Rated flow — actual flow will be lower with media
Liters Per Hour
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Turnover Rate
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Realistic Flow
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GPH = Tank gallons × Turnover rate
Turnover: Light=3×, Moderate=4×, Heavy=6×
Actual flow: Subtract ~20% for media resistance. Clean media monthly.
Turnover: Light=3×, Moderate=4×, Heavy=6×
Actual flow: Subtract ~20% for media resistance. Clean media monthly.
Aquarium Filtration Flow Guide
Proper filtration flow ensures healthy water quality by processing the entire tank volume multiple times per hour. Too little flow leaves dead spots; too much creates stress for certain fish species.
Turnover Rate Guide
| Stocking | Turnover Rate | 55-gal Tank |
|---|---|---|
| Light (few fish) | 3× / hour | 165 GPH |
| Moderate | 4× / hour | 220 GPH |
| Heavy / Messy | 6× / hour | 330 GPH |
Filter Type Considerations
- Canister filters are the gold standard — high flow with excellent mechanical + biological filtration
- HOB filters are easy to maintain but flow drops more as media clogs
- Sponge filters are gentle for fry/shrimp tanks but need higher rated flow
- Sumps provide the most filtration volume and are ideal for large tanks